However, the company realises not all countries will join the trend at the same time. As Robertson says: "Global markets and customers will continue to demand very different drivetrains for a long time to come."

Nod to the future: The new BMW i8 convertible. Pic: Supplied.

BMW aims to give each market the kind of car it prefers.

Its engineers are developing two basic layouts, one for smaller front-drive cars and the other for larger rear-drive vehicles (known internally and respectively as FAAR and CLEAR). Eventually they will provide foundations for every car the BMW Group makes, including Mini and Rolls-Royce.

The pure electric cars will use front and rear sections similar to the versions with internal combustion and plug-in hybrid power. The difference will be in the centre section, where the floor will be made of batteries.

BMW is pushing ahead with electric vehicles. Pic: Supplied

In briefings on the project, engineers have described two modular battery pack designs. The slimmer version, about 80mm thick, will be used in cars and the deeper variant, about 140mm thick, is intended for SUVs.

BMW plans to use different grades of cells in its battery packs so buyers can choose lower cost or longer driving range.

The biggest packs will go into the largest vehicles. These will be Tesla-beaters, able to store more energy and drive further than the American maker's most popular model.

BMW's 120 kWh battery pack will store 20 per cent more energy than a Tesla Model S, and engineers say this will deliver a driving range up to 700km. For smaller cars, it is planning a 90 kWh pack with a range of about 550km and a 60 kWh pack for about 450km.

It's certain that future battery-powered BMWs will be the fastest cars the company makes. Engineers reckon it will be possible to fit three electric motors in top models built on the bigger platform, two driving the rear wheels and one driving the front axle. These will put 500kW-plus to the road, guaranteeing incredible acceleration.

Unlike most other brands, BMW makes its own electric motors and is developing a new generation of less bulky and less costly examples for future models.

These combine motor, single-speed transmission and power electronics in a single casting. As with the battery packs, these can be scaled to suit the size of the vehicle - outputs ranging from 100kW to 300kW-plus are planned.

These new motors will appear first in what BMW engineers describe as "transitional models", including the Mini Electric due in 2019 and the battery-powered version of the BMW X3 scheduled to launch in 2020.

Preparing for e-mobility is clearly a big concern but BMW won't ignore internal combustion and plug-in hybrid propulsion. Robertson promises improvements in the fuel efficiency of its petrol and diesel engines.

BMW engineers also say the performance of future plug-in hybrids will be enhanced with more powerful electric motors and longer electric-only driving ranges.